Allozyme Variation in Mojave Populations of the Desert Tortoise, Gopherus agassizi

Whole blood samples were obtained from a total of 146 desert tortoises from western (Kramer Hills region) and eastern (Chemehuevi Valley) parts of the Mojave Desert in San Bernardino County, California. These samples were examined electrophoretically for allozyme expression at 23 loci, eight of which were polymorphic. Heterozygosity levels and other measures of genetic variability were comparable for the eastern and western Mojave samples. Intrapopulation chi-square tests did not falsify our null hypothesis of random mating at each location. Genetic distance measures and interpopulation FSTvalues suggested that genetic differentiation of eastern and western Mojave Desert tortoises was minimal. However, a contingency chi-square test and multivariate analyses demonstrated significant differences between these geographic samples, falsifying the hypothesis that these Mojave samples are part of a single randomly breeding population. From the perspective of allozyme characteristics, we have no reservations regarding relocation of tortoises between the Kramer and Chemehuevi sites. Allozyme characters of transplanted tortoises should be documented for historical record.